Substrate processing apparatus

CROSS REFERENCE TO RELATED APPLICATIONS

0001This application is a Continuation of U.S. patent application Ser. No. 12/706,958, filed Feb. 17, 2010, and claims the benefit under 35 U.S.C. §119(a)-(d) of Japanese Patent Application No. 2009-38431 filed on Feb. 20, 2009, the entire contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

0002The present invention relates to a substrate processing apparatus comprising a load port in which a transfer container containing a plurality of substrates can be placed, and a container storage part in which the transfer container can be stored, for performing various processes to the substrates which are drawn from the transfer container. In particular, the present invention relates to a substrate processing apparatus capable of efficiently performing a loading operation and an unloading operation of the transfer container.

BACKGROUND OF THE INVENTION

0003Generally, a semiconductor manufacturing apparatus comprises: a load port into which a transfer container containing a plurality of substrates is loaded; a substrate transfer mechanism configured to draw the substrates from the transfer container and to return the processed substrates to the transfer container; and a processing part configured to perform various processes to the substrates. As the transfer container, there is used, instead of a conventional open-type carrier, a FOUP (Front Opening Unified Pod) having a lid member for opening and closing a front surface thereof. Thus, the semiconductor manufacturing apparatus is provided with a mechanism for opening and closing the lid member of the FOUR

0004As a process for a substrate, there are a single-wafer process, such as a vacuum process, and a coating and developing process (a coating process of a resist and a developing process after exposure), and a batch process, such as a thermal process by a vertical thermal processing apparatus and a substrate cleaning process. When a single-wafer process is performed, a substrate is generally drawn from a transfer container placed in a load port. On the other hand, when a batch process is performed, a transfer container is temporarily stored in a container storage part, which is called “stocker” provided between a load port and a processing part, so that stagnation of the transfer containers on the load port can be prevented, whereby a process can be effectively performed.

0005In a cleaning apparatus of a batch type, for example, a batch process is performed such that fifty semiconductor wafers (hereinafter referred to as “wafers”) are arranged in a cleaning container, and the wafers are sequentially immersed into a plurality of cleaning tanks. By improving a mechanism that draws the substrates from the transfer container and transports the substrates to the cleaning container, a series of processes have been recently accelerated. Although there is developed an apparatus whose throughput (process capability) is about six hundred substrates per hour, a still higher throughput is required. For example, assuming that the transfer container can contain twenty-five substrates, in order to process nine hundred substrates per hour, thirty-six transfer containers should be loaded into a load port from a transfer apparatus, specifically, e.g., an overhead transfer apparatus (an in-plant transfer apparatus of a overhead traveling type: OHT), which is disposed on a factory. In this case, the number of times of the loading operations and the unloading operations is seventy-two (36×2).

0006The number of stages for the transfer containers aligned in the load port is generally three or four. However, in order to cope with the above requirement, the number of stages aligned in the load port should be increased to, e.g., about eight. However, when the number of stages aligned therein is increased, a width of the apparatus is widened. Since a rear side area of the lord port is a dead space, the dead space is added to an installation area. As a result, because of the increased installation space, such a structure cannot be employed.

0007JP2008-277764A describes the following technique. Namely, a waiting position, in which a plurality of FOUPs can wait is provided on an upper surface of a ceiling part of a substrate processing apparatus. A FOUP supplied from an overhead transfer apparatus is temporarily located in the waiting position, and then the FOUP is moved by a moving mechanism to a support plate member above a load port. Thereafter, the FOUP is loaded into the load port from the support plate member by the overhead transfer apparatus.

0008JP2008-263004A describes the following structure. Namely, in a CVD apparatus of a single-wafer type, there are formed three load ports by arranging three lower FOUP stages, which can be moved upward and downward, on a front side of three pod openers (lid-member opening and closing mechanism). In addition, three upper FOUP stages are disposed on an upper surface of a sealing of the apparatus body. Thus, FOUPs can be transported between the upper FOUP stages and the lower FOUP stages.

0009Although these techniques can prevent stagnation of the FOUPs in the load port, these techniques have limits to achieving a still higher throughput as described above. Thus, a technique for more improving a throughput has been desired.

SUMMARY OF THE INVENTION

0010The present invention has been made in view of these circumstances. The object of the present invention is to provide a substrate processing apparatus comprising a load port in which a transfer container containing a plurality of substrates is placed, and a container storage part for storing the transfer container, the substrate processing apparatus being capable of increasing the number of times at which the transfer container is transferred to and from the load port, whereby the substrates can be processed with a high throughput.

0011The substrate processing apparatus according to the present invention is a substrate processing apparatus in which a transfer container containing a plurality of substrates is loaded and unloaded by a transfer system comprising: a first transfer path and a second transfer path whose lateral positions differ from each other above the substrate processing apparatus; and a first transfer apparatus and a second transfer apparatus which transfer the transfer container along the first transfer path and the second transfer path, respectively; and the substrates in the transfer container are drawn from the transfer container by a substrate transfer mechanism and are then processed in a processing part, the substrate processing apparatus comprising: a first load port on which a plurality of container tables are linearly arranged correspondingly to the first transfer path, wherein the transfer container is loaded to and unloaded by the first transfer apparatus; a second load port that is arranged stepwise with respect to the first load port at a position higher than the first load port, on which a plurality of container tables are linearly arranged correspondingly to the second transfer path, wherein the transfer container is loaded to and unloaded by the second transfer apparatus; a container table for transporting substrates on which the transfer container is placed for transporting the substrates in the transfer container between the container table and the substrate transfer mechanism; a container storing part disposed rearward the first load port and the second load port, the container storing part including a plurality of container tables on which the plurality of transfer containers are stored; and a container transfer mechanism configured to transfer the transfer container among the container tables of the first load port, the container tables of the second load port, the container tables of the container storing part, and the container table for transporting substrates.

0012The substrate processing apparatus may have the following features. <ul id="ul0001" list-style="none"><li id="ul0001-0001" num="0013">(a) The first load port and the second load port are disposed outside a housing defining an external body of the substrate processing apparatus, and the container storing part is disposed inside the housing; and the container transfer mechanism comprises: an auxiliary transfer mechanism configured to transfer the transfer container between the first load port and an inside position in the housing opposed to the first load port through an opening of the housing; and a main transfer mechanism configured to transfer the transfer container between the inside position and the container table for transporting substrates, and to transfer the transfer container between the respective container tables of the second load port and the container storing part, and the container table for transporting substrates.</li><li id="ul0001-0002" num="0014">(b) The auxiliary transfer mechanism includes a mechanism for horizontally moving the container table of the first load port.</li><li id="ul0001-0003" num="0015">(c) There is provided a shutter for closing the opening, except when the transfer container is moved between the first load port and an area within the housing.</li><li id="ul0001-0004" num="0016">(d) One of the first load port and the second load port is exclusively used for loading the transfer container, and the other thereof is exclusively used for unloading the transfer container.</li><li id="ul0001-0005" num="0017">(e) The first transfer path used in the transfer system is disposed on a floor surface on which the wafer processing apparatus is installed, not being disposed above the substrate processing apparatus.</li></ul>

0018According to the present invention, there is used the transfer system comprising the first transfer path (the first transfer path disposed on a first surface is included) and the second transfer path whose lateral positions differ from each other, and the first transfer apparatus and the second transfer apparatus configured to transfer the transfer container along the first transfer path and the second transfer path, respectively. On the other hand, corresponding to the two in-plant transfer apparatuses, the substrate processing apparatus includes the first load port (lower level) and the second load port (upper level) which are arranged at two levels. Thus, the number of times at which the transfer containers are transported between the in-plant transfer apparatuses and the wafer processing apparatus can be increased, whereby the substrates can be processed with high throughput.

BRIEF DESCRIPTION OF THE DRAWINGS

0019<figref idref="DRAWINGS">FIG. 1</figref> is a schematic view showing a structural example of a system for transferring a FOUP to a wafer cleaning apparatus in one embodiment of the present invention.

0020<figref idref="DRAWINGS">FIG. 2</figref> is a sectional plan view of the wafer cleaning apparatus.

0021<figref idref="DRAWINGS">FIG. 3</figref> is a longitudinal side view showing an inside structure of an interface part disposed in the wafer cleaning apparatus.

0022<figref idref="DRAWINGS">FIG. 4</figref> is a partially cutaway perspective view showing an inside structure of a processing part disposed in the wafer cleaning apparatus.

0023<figref idref="DRAWINGS">FIG. 5</figref> is a partially cutaway perspective view showing a structure of a loading and unloading part disposed in the wafer cleaning apparatus.

0024<figref idref="DRAWINGS">FIG. 6</figref> is a perspective view showing a positional relationship between the loading and unloading part and a transfer path of the FOUP.

0025<figref idref="DRAWINGS">FIG. 7</figref> is a perspective view of a mechanism that slides a tray disposed on a first load port of the loading and unloading part.

0026<figref idref="DRAWINGS">FIG. 8</figref> is a longitudinal sectional view showing an inside structure of the loading and unloading part.

0027<figref idref="DRAWINGS">FIG. 9</figref> is a perspective view showing a structure of a lifter disposed on the loading and unloading part.

0028<figref idref="DRAWINGS">FIG. 10</figref> is a first explanatory view showing an operation of the lifter.

0029<figref idref="DRAWINGS">FIG. 11</figref> is a second explanatory view showing the operation of the lifter.

DETAILED DESCRIPTION OF THE INVENTION

0030Hereafter, there is described an embodiment in which a substrate processing apparatus according to the present invention is applied to a batch-type wafer cleaning apparatus. Firstly, there is briefly described a structure of a wafer transfer system in a semiconductor manufacturing factory in which the wafer cleaning apparatus is installed.

0031<figref idref="DRAWINGS">FIG. 1</figref> shows a schematic structure of a wafer transfer system <b>100</b> in a semiconductor manufacturing factory in which a wafer cleaning apparatus <b>1</b> according to this embodiment is installed. Wafers W are sequentially transferred to various substrate processing apparatuses <b>103</b> which are dispersedly disposed in the factory. The wafers W are subjected to processes, such as a resist coating process, an exposing process, a developing process, an etching process, and a cleaning process, in the respective substrate processing apparatuses <b>103</b>.

0032In the semiconductor manufacturing factory, the plurality of wafers W are contained in, e.g., the aforementioned FOUP as a transfer container. The FOUP is transferred among the substrate processing apparatuses <b>103</b> for performing respective steps, by a transfer robot called “OHT” (Overhead Hoist Transport). In this example, the FOUP can contain a plurality of, e.g., twenty-five wafers W that are horizontally held in a tier-like manner.

0033The transfer system is composed of a rail track disposed on a ceiling part of the factory, and the OHT configured to travel on the rail track. In the semiconductor manufacturing factory, there are formed processing blocks B in which the plurality of substrate processing apparatuses <b>103</b> are gathered in accordance with respective processing steps. A between-step transfer path <b>101</b> formed of the above rail track connects the plurality of processing blocks B to each other. In-step transfer paths <b>102</b> are branched from the between-step transfer path <b>101</b>, and are extended above the substrate processing apparatuses <b>103</b> disposed in the respective processing blocks B, whereby the FOUP can be transported between load ports of the respective substrate processing apparatuses <b>103</b>.

0034In the transfer system as structured above, the processing bock B (which is located on in an upper right area of <figref idref="DRAWINGS">FIG. 1</figref> in this example), in which the wafer cleaning apparatuses <b>1</b> according to this embodiment are disposed, is provided with a multiple in-step transfer path <b>102</b>, e.g., two in-step path <b>102</b>, in order to eliminate mismatch of a processing speed at which the wafers W are processed by the wafer processing apparatuses <b>1</b> and a loading and unloading speed of the FOUP by the transfer system.

0035The FOUP can be transported between the wafer cleaning apparatus <b>1</b> according to this embodiment and the OHT that travels along the multiple step-in transfer path <b>102</b>. Hereafter, a structure of the wafer cleaning apparatus <b>1</b> is described. <figref idref="DRAWINGS">FIG. 2</figref> is a plan view of the wafer cleaning apparatus <b>1</b> according to this embodiment, <figref idref="DRAWINGS">FIG. 3</figref> is a longitudinal side view thereof, and <figref idref="DRAWINGS">FIG. 4</figref> is a perspective view thereof. In these drawings, assuming that the left side thereof is a front side, the wafer cleaning apparatus <b>1</b> comprises a housing <b>11</b> in which a loading and unloading part <b>20</b> through which a FOUP <b>10</b> is loaded and unloaded, an interface part <b>30</b>, and a processing part <b>40</b> configured to perform a liquid process and a drying process for a wafer W, which are arranged, in this order from the front side. The interface part <b>30</b> is configured to adjust a position of the wafer W and to change a posture thereof, in the course of transporting the wafer W, which have been drawn from the FOUP <b>10</b>, between the loading and unloading part <b>20</b> and the processing part <b>40</b>.

0036The loading and unloading part <b>20</b> serves as a part through which the FOUP <b>10</b>, which has been transferred by the OHT traveling along the step-in transfer path <b>102</b>, is loaded into the apparatus <b>1</b>, and also serves as a stock area (stocker) where the vacant FOUP <b>10</b>, from which wafers W have been drawn, is stored during the process of the wafers W. The detailed structure thereof will be described below.

0037As shown in <figref idref="DRAWINGS">FIGS. 2 and 3</figref>, the interface part <b>30</b> separates a space inside the housing <b>11</b> as an external body of the wafer cleaning apparatus from the loading and unloading part <b>20</b> and the processing part <b>40</b> by a front separation wall <b>12</b> and a rear separation wall <b>13</b>. The interface part <b>30</b> is divided into a first interface chamber <b>301</b> and a second interface chamber <b>302</b> by a partition wall <b>14</b>. The first interface chamber <b>301</b> is a space where the unprocessed wafers W are transferred toward the processing part <b>40</b>. In the first interface chamber <b>301</b>, a wafer drawing arm <b>311</b>, a notch aligner <b>32</b>, and a first posture changing apparatus <b>33</b> are provided, respectively.

0038The wafer drawing arm <b>311</b> corresponds to a substrate transfer mechanism of the present invention, and has a function for drawing a wafer W from the FOUP <b>10</b>. When viewed from the front side, the wafer drawing arm <b>311</b> is movable in the right and left direction, movable upward and downward, and rotatable. The notch aligner <b>32</b> is adapted to rotate the respective wafers W, which have been drawn by the wafer drawing arm <b>311</b> and supported on a plurality of plates one by one, and to detect positions of notches formed in the respective wafers W by a photosensor or the like. Thus, the notch positions of the wafers W are aligned by the notch aligner <b>32</b>, whereby the wafers W are arranged in position.

0039The first posture changing apparatus <b>33</b> is adapted to grasp the opposed ends of the side peripheries of the respective wafers W, which have been arranged in position by the notch aligner <b>32</b>, and to horizontally hold the wafers W in a tier like manner in the up and down direction. After adjusting the intervals between the wafers W, as schematically shown in <figref idref="DRAWINGS">FIG. 3</figref>, the first posture changing apparatus <b>33</b> changes the horizontal posture of the respective wafers W to the vertical posture, by rotating the wafers W arranged in a tier-like manner at 90 degrees while grasping the opposed ends of the respective wafers W. In <figref idref="DRAWINGS">FIG. 3</figref>, the wafers W in the horizontal posture are shown by the solid lines, and the wafers W in the vertical posture are shown by the broken lines. The first posture changing apparatus <b>33</b> also correspond to the substrate transfer mechanism of the present invention.

0040On the other hand, the other second interface chamber <b>302</b> divided by the partition wall <b>14</b> is a space where the wafers W, which have been processed by the processing part <b>40</b>, are transferred toward the FOUP <b>10</b>. In the second interface chamber <b>302</b>, a transport arm <b>35</b>, a second posture changing apparatus <b>34</b>, and a wafer delivering arm <b>312</b> are provided, respectively. The transport arm <b>35</b>, the second posture changing apparatus <b>34</b>, and the wafer delivering arm <b>312</b> correspond to the substrate transfer mechanism of the present invention.

0041The transport arm <b>35</b> receives the wafers W, which have been processed by the processing part <b>40</b> and are still arranged in the vertical state, and transfers the same. Contrary to the first posture changing apparatus <b>33</b>, the second posture changing apparatus <b>34</b> has a function for changing the vertical posture of the wafers W to the horizontal posture. The wafer delivering arm <b>312</b> has substantially the similar structure as that of the aforementioned wafer drawing arm <b>311</b>. The wafer delivering arm <b>312</b> is adapted to deliver the wafers W, which have been changed to the horizontal posture by the second posture changing apparatus <b>34</b>, into the FOUP <b>10</b> stored in the loading and unloading part <b>20</b>.

0042The processing part <b>40</b> includes a first processing unit <b>41</b> configured to remove particles and organic contaminations adhering to the wafers W that have been transferred from the interface part <b>30</b>, a second processing unit <b>42</b> configured to remove metal contaminations adhering to the wafers W, a cleaning and drying unit <b>43</b> configured to remove chemical oxide films formed on the wafers W and dry the wafers W, a transfer arm <b>45</b> configured to transfer the wafers W among these units <b>41</b> to <b>43</b>, and a chuck cleaning unit <b>44</b> configured to clean a wafer holding chuck disposed on the transfer arm <b>45</b>.

0043As shown in <figref idref="DRAWINGS">FIGS. 2 and 4</figref>, in the processing unit <b>40</b>, the cleaning and drying unit <b>43</b>, the second processing unit <b>42</b>, the first processing unit <b>41</b>, and the chuck cleaning unit <b>44</b> are linearly arranged in this order from the front side. The transfer arm <b>45</b> is movable upward and downward and rotatable.

0044In addition, the transfer arm <b>45</b> is movable in the fore and aft direction by a transfer track <b>46</b> disposed along the units <b>41</b> to <b>44</b> so as to guide the transfer arm <b>45</b>. The function of the transfer arm <b>45</b> is to transfer and transport the wafers W among the respective units <b>41</b> to <b>43</b> and the interface part <b>30</b>. The transfer arm <b>45</b> can transfer a plurality of, e.g., fifty wafers W in the vertical posture.

0045The first and second processing units <b>41</b> and <b>42</b> are structured as processing tanks capable of being filled with a chemical liquid, such as APM (Ammonium hydroxide-hydrogen Peroxide-Mixture) solution (mixture solution of ammonia, hydrogen peroxide solution, and deionized water) and HPM (HCl-hydrogen Peroxide-Mixture) solution (mixture solution of hydrochloric acid, hydrogen peroxide solution, and deionized water). The processing units <b>41</b> and <b>42</b> are equipped with wafer boats <b>411</b> and <b>421</b>, respectively. The boats <b>411</b> and <b>421</b> can collectively transport the wafers W between the processing units <b>41</b> and <b>42</b> and the transfer arm <b>45</b>, and can immerse the wafers W into the chemical liquid.

0046On the other hand, the cleaning and drying unit <b>43</b> is structured as a processing tank capable of being filled with a chemical liquid, e.g., hydrofluoric acid, for removing a chemical oxide film formed on a surface of the wafer W. The cleaning and drying unit <b>43</b> is equipped with a wafer boat <b>431</b> similar to those of the first and second processing units <b>41</b> and <b>42</b>. In addition, after the removal of oxide film, in order to dry the wafers W, the cleaning and drying unit discharges the chemical liquid in the processing tank and supplies a drying steam (concretely, isopropyl alcohol (IPA) gas, for example) in the processing tank. For this purpose, the cleaning and processing unit <b>43</b> can form a sealed space by covering the processing tank with a hood <b>432</b>. The chuck cleaning unit <b>44</b> has a function for cleaning the wafer holding chuck disposed on the transfer arm <b>45</b> by supplying thereto a deionized water, and thereafter drying the wafer holding chuck by supplying thereto a drying gas such as N₂gas and an air.

0047In the wafer cleaning apparatus <b>1</b> as structured above, the loading and unloading part <b>20</b> has the structure in which the FOUP <b>10</b> can be transported between the loading and unloading part <b>20</b> and the OHT traveling along the in-step transfer path <b>102</b>. By utilizing the two in-step transfer path <b>102</b>, even in the wafer cleaning apparatus <b>1</b> capable of processing many wafers W, e.g., nine hundred wafers W per hour, the FOUPs <b>10</b> can be loaded and unloaded, without decelerating a process speed of the wafers W. Herebelow, the detailed structure of the loading and unloading part <b>20</b> is described.

0048As shown in <figref idref="DRAWINGS">FIGS. 5 and 6</figref>, the loading and unloading part <b>20</b> in this embodiment includes a first load port <b>21</b> and a second load port <b>22</b>, which are arranged at two levels on a front surface of the loading and unloading part <b>20</b> (outside the housing <b>11</b> defining the external body of the wafer cleaning apparatus <b>1</b>). The first load port <b>21</b> is disposed on the forefront of the loading and unloading part <b>20</b>, and is structured as a table on which a plurality of, e.g., four FOUPs <b>10</b> can be linearly placed in the width direction. The first load port <b>21</b> is located at a height position accessible not only from the step-in transfer path <b>102</b> but also from an operator and an AGV (Automated Guided Vehicle).

0049The second load port <b>22</b> is arranged stepwise on a position which is rearward the first load port <b>21</b> by a space corresponding to one FOUP <b>10</b>, and is higher than the first load port <b>21</b> that is located at an about one-meter height position from a floor surface. Similarly to the first load port <b>21</b>, the second load port <b>22</b> is structured as a table on which a plurality of, e.g., four FOUPs <b>10</b> can be linearly placed in the width direction. The second load port <b>22</b> is located at position which does not interfere with a height at which the FOUP <b>10</b> is transferred by means of the OHT. This position is also a highest at which the FOUPs <b>10</b> can be loaded into the loading and unloading part <b>20</b> and unloaded therefrom in the lateral direction, within a range from an upper part of the below-described openings <b>210</b> formed in the first load port <b>21</b> and a ceiling surface of the housing <b>11</b> of the wafer cleaning apparatus <b>1</b>. The height up to the ceiling surface of the apparatus <b>1</b> is limited to, e.g., the transfer height of the FOUP <b>10</b>. The transfer height of the FOUP <b>10</b> may be determined in conformity to the SEMI (Semiconductor Equipment and Materials International) standard. Thus, the space inside the loading and unloading part <b>20</b> can be enlarged, whereby the number of FOUPs <b>10</b> to be placed in the below-described stock area can be increased.

0050As shown in <figref idref="DRAWINGS">FIGS. 6 and 8</figref>, the wafer cleaning apparatus <b>1</b> is installed such that the area on which the FOUPs <b>10</b> are linearly placed on the first load port <b>21</b> corresponds to the one step-in transfer path <b>102</b>A serving as a first transfer path, and that the area on which the FOUPs <b>10</b> are linearly placed on the second load port <b>22</b> corresponds to the other step-in transfer path <b>102</b>B serving as a second transfer path. Thus, the FOUPs <b>10</b> are transported to the first load port <b>21</b> only from the OHT <b>104</b>A serving as a first transfer apparatus traveling along the step-in transfer path <b>102</b>A. On the other hand, the FOUPs <b>10</b> are transported to the second load port <b>22</b> only from the OHT <b>104</b>B serving as a second transfer apparatus traveling along the step-in transfer path <b>102</b>B.

0051In the following example, although there is described a case in which the first load port <b>21</b> is exclusively used for loading the FOUPs <b>10</b> to the wafer cleaning apparatus <b>1</b>, and the second load port <b>22</b> is exclusively used for unloading the FOUPs <b>10</b> from the wafer cleaning apparatus <b>1</b>, the use of the load ports <b>21</b> and <b>22</b> is not limited to the example.

0052The first load port <b>21</b> is provided with trays <b>212</b> serving as container tables disposed at positions where the FOUPs <b>10</b> are placed. In a side surface of the housing <b>11</b> of the loading and unloading part <b>20</b>, there are formed openings <b>210</b> at positions opposed to the FOUPs <b>10</b> on the respective trays <b>212</b>.

0053Each tray <b>212</b> is configured to be slidable in the fore and aft direction (movable in the horizontal direction). <figref idref="DRAWINGS">FIG. 7</figref> shows a structure for sliding the tray <b>212</b>. Elongated plate-like rail members <b>213</b> are secured below the tray <b>212</b> with a gap therebetween in the right and left direction when viewed from the front. The mechanism for sliding the tray <b>212</b> is disposed in a flat space defined between these rail members <b>213</b> and the tray <b>212</b>. Included in this space are a first air cylinder <b>215</b> secured on a floor surface of the first load port, a plate <b>216</b> secured on a forefront end of an operating rod of the first air cylinder <b>215</b>, and a second air cylinder <b>217</b> secured on the plate <b>216</b>.

0054The tray <b>212</b> is secured on an operating rod of the second air cylinder <b>217</b> at a rear surface thereof. When the first air cylinder <b>215</b> is operated, the three members, i.e., the plate <b>216</b>, the second air cylinder <b>217</b>, and the tray <b>212</b>, are pushed toward the opening <b>210</b>, and when the second air cylinder <b>217</b> is further operated, the tray <b>212</b> is further pushed. Namely, a two-stage stroke structure is provided. Thus, the tray <b>212</b> can be slid, so that the FOUP <b>10</b> placed on the tray <b>212</b> can be moved between the first load port <b>21</b> and the loading and unloading part <b>20</b>.

0055The aforementioned mechanism for sliding the tray <b>212</b> corresponds to an auxiliary transfer mechanism which is one of container transfer mechanisms for transferring the FOUP <b>10</b> between the first load port <b>21</b> and the inside position in the housing <b>11</b> opposed to the first load port <b>21</b> through the opening <b>210</b>. In the drawings other than <figref idref="DRAWINGS">FIG. 7</figref>, illustration of the mechanism such as the first and second air cylinders <b>215</b> and <b>217</b> for sliding the tray <b>212</b> is omitted.

0056As described above, since the first load port <b>21</b> is disposed at the height position accessible from a person, as shown in <figref idref="DRAWINGS">FIGS. 7 and 8</figref>, each opening <b>210</b> can be closed by a shutter <b>211</b> except when the FOUP <b>10</b> is moved through the opening <b>210</b>. The reference number <b>218</b> in <figref idref="DRAWINGS">FIG. 7</figref> depicts a pin for securing the FOUP <b>10</b> on the tray <b>212</b>.

0057Next, the second load port <b>22</b> is described. The second load port <b>22</b> is also provided with trays <b>221</b> serving as container tables disposed at positions where the FOUPs <b>10</b> are placed. In the side surface of the housing <b>11</b> of the loading and unloading part <b>20</b>, there is formed an opening <b>220</b> at a position opposed to the FOUPs <b>10</b> placed on the respective trays <b>221</b>. In this example, since the FOUP <b>10</b> placed on the second load port <b>22</b> is loaded into the loading and unloading part <b>20</b> by, e.g., a lifter <b>23</b>A, which is described below, the tray <b>221</b> on the second load port <b>22</b> does not have a slidable structure. Since the opening <b>220</b> is disposed at a height position that is difficult to be accessible from a person, the opening <b>220</b> in the second load port <b>22</b> is not provided with a shutter. A shape of the opening <b>220</b> differs from that of the opening of the first load port <b>21</b>, i.e., the opening <b>220</b> is of an elongated opening shape corresponding to the four trays <b>221</b>.

0058As shown in <figref idref="DRAWINGS">FIGS. 5 and 8</figref>, a plurality of holding plates <b>241</b> are attached to, e.g., a wall surface of the separation wall <b>12</b> disposed in the loading and unloading part <b>20</b> for separating the loading and unloading part <b>20</b> and the interface part <b>30</b>. In this example, for example, sixteen holding plates <b>241</b> are disposed in a four by four arrangement (four stages and four rows). In addition, four holding plates <b>241</b> in a one by four arrangement (one stage and four rows) are attached to the inside wall surface of the housing <b>11</b> below the second load port <b>22</b>. Namely, the total of twenty holding plates <b>241</b> are disposed rearward (back surface side) of the first load port <b>21</b> and the second load port <b>22</b>. These holding plates <b>241</b> serve as the container tables on which the vacant FOUPs <b>10</b> from which the wafers W have been drawn can be placed. The areas on which the holding plates <b>241</b> are disposed correspond to stock areas <b>24</b> for the FOUPs <b>10</b>. The stock areas <b>24</b> correspond to the container storing part of the present invention. As a matter of course, the FOUP <b>10</b> containing the wafers W can be placed in the stock area <b>24</b>.

0059In the loading and unloading part <b>20</b>, the stock areas <b>24</b> are opposedly disposed along the side wall surface of the housing <b>11</b> on the front side and the surface of the separation wall <b>12</b> on the rear side. As shown in <figref idref="DRAWINGS">FIG. 8</figref>, formed between the stock areas <b>24</b> is an elevation space <b>28</b> in which the FOUP <b>10</b> can be elevated and lowered. As shown in <figref idref="DRAWINGS">FIGS. 1, 8, and 10</figref>, disposed in the elevation space <b>28</b> are the two lifters <b>23</b>A and <b>23</b>B serving as a main transfer mechanism which is one of the container transfer mechanisms of the present invention. When viewed from the front, the lifters <b>23</b>A and <b>23</b>B are horizontally extended from the right and left inner wall surfaces. Due to the lifters <b>23</b>A and <b>23</b>B, the FOUPs <b>10</b> can be freely transferred in the loading and unloading part <b>20</b>.

0060As shown in <figref idref="DRAWINGS">FIG. 9</figref>, each of the lifters <b>23</b>A and <b>23</b>B has a structure in which grasping parts <b>234</b> for grasping a top flange of the FOUP <b>10</b> are disposed on opposed ends of an elongated plate-like fixing plate <b>233</b> that is extended in the right and left direction when viewed from the front side. Thus, the two FOUPs <b>10</b> can be simultaneously transferred by the respective lifters <b>23</b>A and <b>23</b>B. The fixing plate <b>233</b> is disposed on a distal end position of a scalar arm part <b>232</b> which is capable of extending in the fore and aft direction. An expandable arm part <b>231</b>, which is capable of expanding and contracting in the right and left direction when viewed from the front side, is connected to a proximal end of the scalar arm part <b>232</b>. A proximal end of the expandable arm part <b>231</b> is configured to be movable upward and downward along an elevation rail <b>25</b>.

0061Thus, as shown in <figref idref="DRAWINGS">FIG. 8</figref>, the lifters <b>23</b>A and <b>23</b>B are capable of moving upward and downward. Further, as shown in <figref idref="DRAWINGS">FIGS. 8 and 10</figref>, the lifters <b>23</b>A and <b>23</b>B are capable of extending in the fore and aft direction. Furthermore, as shown in <figref idref="DRAWINGS">FIG. 11</figref>, the lifters <b>23</b>A and <b>23</b>B are capable of expanding and contracting in the right and left direction when viewed from the front side. Thus, the lifters <b>23</b>A and <b>23</b>B can access the FOUPs <b>10</b> located in respective areas of the loading and unloading part <b>20</b>, i.e., the FOUPs <b>10</b>, which have been loaded into the loading and unloading part <b>20</b> (inside position of the housing <b>11</b>) by sliding the trays <b>212</b>, the FOUPs <b>10</b> placed on the second load port <b>22</b>, the FOUPs <b>10</b> stored in the stock areas <b>24</b>, and the FOUPs <b>10</b> placed on ports <b>26</b> and <b>27</b>, which are described below, for accessing the interface part <b>30</b>. As shown in <figref idref="DRAWINGS">FIG. 11</figref>, when the expandable arm part <b>231</b> of one of the lifters <b>23</b>A and <b>23</b>B is expanded, the other of the lifters <b>23</b>A and <b>23</b>B is retracted upward or downward.

0062As shown in <figref idref="DRAWINGS">FIG. 10</figref>, in the loading and unloading part <b>20</b>, four ports <b>26</b> and <b>27</b> for accessing the interface part <b>30</b> are linearly arranged at a position below the rear stock areas <b>24</b>. Among the four ports, the two ports disposed on the right side when viewed from the front side of the wafer cleaning apparatus <b>1</b> are the outlet ports <b>26</b> through which the wafers W are drawn from the FOUP <b>10</b> toward the first interface chamber <b>301</b>, and the two ports disposed on the left side are the inlet ports <b>27</b> through which the wafers W are delivered the FOUP <b>10</b> from the second interface chamber <b>302</b>. These outlet ports <b>26</b> and the inlet ports <b>27</b> correspond to a container table for transporting substrates of the present invention.

0063In front of each of the access ports <b>26</b> and <b>27</b>, there is disposed an opening and closing door <b>121</b> which can be moved upward and downward between a position opposed to the FOUP <b>10</b> and a retracted position therebelow. The opening and closing door <b>121</b> can open and close the lid member disposed on the side surface of the FOUP <b>10</b>, for drawing the wafers W from the FOUP <b>10</b> and delivering the wafers W into the FOUP <b>10</b>.

0064As shown in <figref idref="DRAWINGS">FIG. 2</figref>, the wafer cleaning apparatus <b>1</b> as structured above is connected to a control device <b>5</b>. The control device <b>5</b> is formed of, e.g., a computer, not shown, including a CPU and a storage part. The storage part stores a program including a control step (instruction) group. In accordance with the control step group, the FOUPs <b>10</b> are loaded into the respective loading and unloading parts <b>20</b>, the wafers W are drawn therefrom and are subjected to various liquid processes, the wafers W are then delivered into the FOUPs <b>10</b>, and the FOUPs <b>10</b> are unloaded. This program is stored in a storage medium, such as a hard disc, a compact disc, a magneto optical disc, and a memory card, and is installed in the computer.

0065An operation of the wafer cleaning apparatus <b>1</b> as structure above is described. As shown in <figref idref="DRAWINGS">FIG. 8</figref>, the FOUP <b>10</b> containing the wafers W, which haven been processed by another substrate processing apparatus <b>103</b>, is transferred by the OHT <b>104</b>A along the step-in transfer path <b>102</b>A. When the FOUP <b>10</b> reaches the upper part of the wafer cleaning apparatus of this embodiment, the OHT <b>104</b>A extends an elevation belt <b>105</b> so as to lower the FOUP <b>10</b>, such that the FOUP <b>10</b> is placed on one of the trays <b>212</b> of the first load port <b>21</b>.

0066After the FOUP <b>10</b> has been placed on the first load port <b>21</b>, the shutter <b>211</b> is opened, and the tray <b>212</b> is slid so as to load the FOUP <b>10</b> into the loading and unloading part <b>20</b>. Then, the FOUP <b>10</b> is lifted up from the tray <b>212</b> by the lifter <b>23</b>A, for example, which is disposed on the right side when viewed from the front, and the FOUP <b>10</b> is placed on the outlet port <b>26</b>. The lid member of the FOUP <b>10</b> placed on the outlet port <b>26</b> is detached by the opening and closing door <b>121</b>. Then, the wafer drawing arm <b>311</b> enters the FOUP <b>10</b> so that the wafers W are drawn therefrom and loaded into the first interface chamber <b>301</b>. The lid member of the vacant FOUP <b>10</b> from which the wafers W have been drawn is closed, and the FOUP <b>10</b> is transferred by, e.g., the lifter <b>23</b>A to the stock area <b>24</b>. In the stock area <b>24</b>, the FOUP <b>10</b> is stored until the process for the wafers W is finished.

0067The wafers W loaded into the first interface chamber <b>301</b> are positioned by the notch aligner <b>32</b>, and the gaps therebetween and the postures thereof are adjusted and changed by the first posture changing apparatus <b>33</b>. Thereafter, the wafers W are transported to the transfer arm <b>45</b> entering the interface part <b>30</b>. The wafers W held by the transfer arm <b>45</b> are transported to the wafer boat <b>411</b> of the first processing unit <b>41</b>. Then, the wafers W are immersed into the APM solution in the processing tank. After particles and organic contaminations have been removed, the wafers W are cleaned by a cleaning liquid (e.g., deionized water).

0068The wafers W, which have been subjected to the primary cleaning process in the first processing unit <b>41</b>, are again transported to the transfer arm <b>45</b>, and are transported to the wafer boat <b>421</b> of the second processing unit <b>42</b>. Then, the wafers W are immersed into a chemical liquid such as the HPM solution. After metal contaminations have been removed, the wafers W are cleaned by deionized water. The wafers W, which have been subjected to the secondary cleaning process, are again transported to the transfer arm <b>45</b>. The wafers W are transferred to the cleaning and drying unit <b>43</b> and transported to the wafer boat <b>431</b>. Then, a removal process for removing chemical oxide films by hydrofluoric acid, and a drying process by IPA gas are performed.

0069After the dried wafers W have been transported to the transport arm <b>35</b> in the second interface chamber <b>302</b>, the posture of the wafers W is changed from the vertical state to the horizontal state by the second posture changing apparatus <b>34</b>. Simultaneously with this operation, the lifter <b>23</b>B, for example, disposed on the left side when viewed from the front side, transfers the FOUP <b>10</b> stored in the stock area <b>24</b> to the inlet port <b>27</b>. On the inlet port <b>27</b>, the FOUP <b>10</b> waits with its lid member being detached by the opening and closing door <b>121</b>.

0070The wafer delivering arm <b>312</b> loads the wafers W from the second posture changing apparatus <b>34</b> into the FOUP <b>10</b> on the inlet port <b>27</b>. After the wafers W have been loaded thereinto, the lid member is closed. Then, the FOUP <b>10</b> is lifted by, e.g., the lifter <b>23</b>B, and is elevated in the elevation space <b>28</b>, so that the FOUP <b>10</b> is placed on the second load port <b>22</b>. The FOUP <b>10</b> placed on the second load port <b>22</b> is lifted from the second load port <b>22</b> by the OHT <b>104</b>B traveling along the step-in transfer path <b>102</b>B extended above the second load port <b>22</b>, and is then transferred to the succeeding substrate processing apparatus <b>103</b>. In the wafer cleaning apparatus <b>1</b>, the aforementioned operation is continuously repeated, whereby the nine hundred wafers W per hour, for example, are processed.

0071According to the wafer cleaning apparatus <b>1</b> in this embodiment, the following effects can be produced. There is used the transfer system including the step-in transfer paths <b>102</b>A and <b>102</b>B serving as the first transfer path and the second transfer path whose lateral positions differ from each other above the wafer cleaning apparatus <b>1</b>, and the OHTs <b>104</b>A and <b>104</b>B which respectively transfer the FOUPs <b>10</b> along the step-in transfer paths <b>102</b>A and <b>102</b>B. On the other hand, correspondingly to the two OHTs <b>104</b>A and <b>104</b>B, the wafer cleaning apparatus <b>1</b> includes the first load port <b>21</b> (lower level (the first load port <b>21</b> is accessible from a floor side by a person and an AGV)) and the second load port <b>22</b> (upper level) which are arranged at two levels. Thus, the number of times at which the FOUPs <b>10</b> are transported between the OHTs <b>104</b>A and <b>104</b>B and the wafer cleaning apparatus <b>1</b> can be increased, whereby the wafers W can be processed with high throughput.

0072In addition, the FOUPs <b>10</b> are loaded and unloaded, with the first load port <b>21</b> being exclusively used for loading and the second load port <b>22</b> being exclusively used for unloading. Thus, the FOUP loading operation and the FOUP unloading operation by the OHTs <b>104</b> traveling along the two step-in transfer path <b>102</b> do not cross each other, so that the FOUPs <b>10</b> can be smoothly loaded and unloaded. However, the use of the first and second load ports <b>21</b> and <b>22</b> are not limited to the above case, and the wafers W may be loaded and unloaded on both the load ports <b>21</b> and <b>22</b>.

0073As described with reference to <figref idref="DRAWINGS">FIGS. 5 and 6</figref>, in this example, the height position at which the second load port <b>22</b> is disposed is the highest height position within a constraint range of the apparatus height of the wafer cleaning apparatus <b>1</b>, such that the height position of the second load port <b>22</b> does not interfere with a height at which the FOUP <b>10</b> is transferred by the OHT, which is determined by the SEMI standard, for example. Thus, the space in the loading and unloading part <b>20</b> can be enlarged, so that the number of FOUPs <b>10</b> to be placed in the stock areas <b>24</b> can be increased as much as possible. Therefore, for example, an OHT that travels at a height position higher than the SEMI standard may be developed so as to make higher the apparatus height of the wafer cleaning apparatus <b>1</b>, and the second load port <b>22</b> may be disposed at a higher height position correspondingly thereto. In this case, the number of FOUPs <b>10</b> to be placed in the stock areas <b>24</b> can be increased.

0074On the other hand, the height position at which the second load port <b>22</b> is disposed is not limited to the uppermost position of the apparatus height of the wafer cleaning apparatus <b>1</b>, and the second load port <b>22</b> may be disposed at a lower position. When the FOUPs <b>10</b> are loaded and unloaded, the effect of the present invention can be obtained, as long as the wafer cleaning apparatus <b>1</b> and the second load port <b>22</b> are arranged stepwise in this order from below, and vertical trajectories along which the FOUPs <b>10</b> are transported between the step-in transfer paths <b>102</b>A and <b>102</b>B and horizontal trajectory through which the FOUPs are loaded and unloaded with respect to the loading and unloading part <b>20</b> do not intersect with each other, i.e., do not interfere with each other.

0075Further, the number of the load ports disposed on the loading and unloading part <b>20</b> of the wafer cleaning apparatus <b>1</b> is not limited to two, and three or more load ports may be disposed in accordance with the number of the step-in transfer paths <b>102</b> disposed in the processing block B. In this case, the lower load port of the selected two load ports disposed on the loading and unloading part <b>20</b> corresponds to the first load port, and the upper load port thereof corresponds to the second load port.

0076Furthermore, not limited to the batch-type cleaning apparatus, the first load port and the second load port of the present invention, which are arranged stepwise, may be applied to a coating and developing apparatus.

0077In the wafer cleaning apparatus <b>1</b> in this embodiment, although the first transfer path used in the transfer system is disposed above the wafer processing apparatus <b>1</b>, the first transfer path may be disposed on a floor surface on which the wafer processing apparatus is installed.